what we're talking about here, wolf, so still a relatively new science. it's still emerging. 35 football players that have been examined at one particular laboratory in boston, of them, 34 did have evidence of this cte. but keep in mind, wolf, that these were also players that for one reason or another, their brains were being studied. so there was already some concern. it's going to take more study to sort of establish that connection, but one thing the researchers did tell me is that cte, they have not found anything else that causes it, except for repeated blows to the head. and by the way, not just concussions, wolf, but even what are known as sub-concussive hits. the kind of player where you see a player take a hit, but they get right back up, seemingly nothing wrong, those can accumulate according to some of these researchers and cause some of these problems later on down the line. >> which players, sanjay, are at the highest risks for cte? >> we're not entirely sure. we do know that the more hits, the worse off you are. so if you start football ear